Exam 3 Chapters 27 28 31

Recently, a microbe that is able to digest cellulose was discovered in a hot spring with an average temperature of 95°C. Predict the group to which this microbe most likely belongs.

Archaea

Which of the following is least associated with the others? A. horizontal gene transfer B. binary fission C. transformation D. conjugation

B

Fairy Ring: What is the most probable location of the oldest portion of this mycelium?

C

Which of the following results would support Simard et al.'s (1997) hypothesis that fungi can move carbon from one plant to another? [Hypothesis: Sugars made by one plant during photosynthesis can travel through a mycorrhizal fungus and be incorporated into the tissues of another plant.]

Carbon-14 is found in the Douglas fir seedling's tissues and carbon-13 in the birch

A fungal spore germinates, giving rise to a mycelium that grows outward into the soil surrounding the site where the spore originally landed. Which of the following accounts for the fungal movement, as described here?

Cytoplasmic Streaming in Hyphae

Assume that all four locations are 0.5 meters above the surface. On a breezy day with prevailing winds blowing from left to right, where should one expect to find the highest concentration of free basidiospores in an air sample?

D

Fairy Ring: At which location should one find the lowest concentration of fungal enzymes, assuming that the enzymes do not diffuse far from their source and that no other fungi are present in this habitat?

D

Which two genera have members that can evade the human immune system by frequently changing their surface proteins?

Plasmodium and Trypanosoma

If the fungus that produced the fairy ring can also produce arbuscules, then which of the following is most likely to be buried at location "C"?

Tree stump

Green algae differ from land plants in that many green algae__________.

are unicellular.

Arrange the following in order from largest to smallest.

ascomycete, ascocarp, ascus, ascospore

The pathogenic prokaryotes that cause cholera are _____.

bacteria that release an exotoxin.

Similar to most amoebozoans, the forams and the radiolarians also have pseudopods, as do some of the white blood cells of animals (monocytes). If one were to erect a taxon that included all organisms that have cells with pseudopods, the taxon would _____.

be polyphyletic.

"Rare events" can help us understand evolutionary events, as shown in the figure. Which of the following statements explains the logic of this approach?

because mutation only occurred once, all organisms have common ancestor with mutation.

A gelatinous seaweed that grows in shallow, cold water and undergoes heteromorphic alternation of generations is most probably what type of alga?

brown algae

Apart from direct amphibian-to-amphibian contact, what is the most likely means by which the zoospores spread from one free-living amphibian to another?

by flagella.

Orchid seeds are tiny, with virtually no endosperm and with miniscule cotyledons. If such seeds are deposited in a dark, moist environment, then which of the following represents the most likely means by which fungi might assist in seed germination, given what the seeds lack?

by providing the embryos with some of the organic nutrients the fungi have absorbed

When a mosquito infected with Plasmodium first bites a human, the Plasmodium _____.

cells infect human liver cells

Which of the following have chloroplasts (or structures since evolved from chloroplasts) thought to be derived from ancestral green algae?

chlorarachniophytes

Which process in Paramecium results in genetic recombination but no increase in population size?

conjugation

Reinforced, threadlike pseudopods that can perform phagocytosis are generally characteristic of ________.

foramifera

A porous test (shell) of calcium carbonate, through which pseudopodia protrude, is characteristic of ________.

foraminiferans

Dinoflagellates

possess two flagella

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the question(s) below Which two species should have much more phospholipid, in the form of bilayers, in their cytoplasms than most other bacteria?

species B and E

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following question. Which species is capable of directed movement?

species C

What is the most likely explanation for the observation that total biomass (graph e) does not vary with AMF diversity?

Bromus erectus is the dominant plant species.

What is the major difference between Bromus erectus (graph f) and the other plant species (graphs a-d) included in the study?

Bromus erectus is unaffected by AMF diversity.

At which location is the mycelium currently absorbing the most nutrients per unit surface area, per unit time?

A

If a bacterium regenerates from an endospore that did not possess any of the plasmids that were contained in its original parent cell, the regenerated bacterium will probably also lack ________.

antibiotic-resistant genes.

Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?

extreme halophiles

Use of synthetic fertilizers often leads to the contamination of groundwater with nitrates. Nitrate pollution is also a suspected cause of anoxic "dead zones" in the ocean. Which of the following might help reduce nitrate pollution?

growing improved crop plants that have nitrogen-fixing enzymes.

Which process could have allowed the nucleomorphs of chlorarachniophytes to be reduced, without the net loss of any genetic information?

horizontal gene transfer

Which of the following results would be most important in determining whether P. chromatophora's chromatophore is still an endosymbiont, or is an organelle, as the term chromatophore implies?

if there has been movement of genes from the chromatophore genome to the nuclear genome, such that these genes are no longer present in the chromatophore genome

Giardia's mitosome can be said to be "doubly degenerate," because it is a degenerate type of ________, an organelle that is itself a degenerate form of ________.

mitochondria, proteo-bacterium

Which of the following best describes the physical relationship of the partners involved in lichens?

Photosynthetic cells are surrounded by fungal hyphae.

A billionaire buys a sterile volcanic island that recently emerged from the sea. To speed the arrival of conditions necessary for plant growth, the billionaire might be advised to aerially sow what over the island?

soredia

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the question(s) below Which two species might be expected to cooperate metabolically, perhaps forming a biofilm wherein one species surrounds cells of the other species?

species A and B

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the question(s) below Which species is most likely to be found in sewage treatment plants and in the guts of cattle?

species B

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the question. Species D is pathogenic if it gains access to the human intestine. Which other species, if it coinhabited a human intestine along with species D, is most likely to become a recombinant species that is both pathogenic and resistant to some antibiotics?

species C

Referring to Simard et al. (1997), which design element is the control in this experiment and why?

the cedar seedling, because it does not form ectomycorrhizal connections with the tested fungus.

Many chlorophytes are unicellular, but others are bigger and more complex. The fact that increased size and complexity evolved in different ways indicates ________.

the chlorophyte group contained extensive genetic variability

According to the endosymbiotic theory, why was it adaptive for the larger (host) cell to keep the engulfed cell alive, rather than digesting it as food?

the engulfed cell provided the host with ATP

What do fungi and arthropods have in common?

Both groups use chitin for support.

All protist are_____________.

Eukaryotic

Diploid nuclei of the ascomycete Neurospora crassa contain 14 chromosomes. A single diploid cell in an ascus will undergo one round of meiosis, followed in each of the daughter cells by one round of mitosis, producing a total of eight ascospores. If a single, diploid G2 nucleus in an ascus contains 400 nanograms (ng) of DNA, then a single ascospore nucleus of this species should contain how much DNA (ng), carried on how many chromosomes?

100 ng on 7 chromosomes

Which location is nearest to basidiocarps?

A

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains NO PLASMIDS and relatively little peptidoglycan. Adherence to the intestinal lining by this bacterium is due to its possession of _____.

A Capsule

A researcher took water in which a Jl population had been thriving, filtered the water to remove all bacterial cells, and then applied the water to the skins of adult amphibians to see if there would subsequently be a reduced infection rate by Bd when frog skins were inoculated with Bd. For which of the following hypotheses is the procedure described a potential test?

A toxin secreted by Jl cells kills Bd cells when both are present together on frog skin

SAR is a group defined by DNA similarities. This grouping represents ________.

A hypothesis about evolutionary history.

In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. E. coli cells typically make most of their ATP by metabolizing glucose. Under the conditions of this experiment, E. coli generation times in the experimental lines and low-glucose conditions should ________.

Be slower than in the typical environment.

Based on the graphs in the figure, which of the following plant species is most likely not to form mycorrhizal associations?

Carex Flacca (graph A)

While examining a rock surface, you have discovered an interesting new organism. Which of the following criteria will allow you to classify the organism as belonging to Bacteria but not Archaea or Eukarya?

Cell walls are made primarily of peptidoglycan.

You are given an unknown organism to identify. It is unicellular and heterotrophic. It is motile, using many short extensions of the cytoplasm, each featuring the 9 + 2 filament pattern. It has well-developed organelles and two nuclei, one large and one small. This organism is most likely to be a _____.

Ciliate

Which of the following characteristics would be most helpful in distinguishing among different species of fungi?

DNA sequence

Bacteria perform each of the following ecological roles. Which role typically does not involve symbiosis?

Decomposer

which of the following groups is matched with a correct anatomical feature?

Diatoms - Tests made from cellulose.

Some nematode worms suck plant juices from the roots of plants and are economically important agricultural pests. Some fungi are usually decomposers of plant material, but some trap and kill nematodes at times. Arthrobotrys traps and kills nematodes, especially when they lack nitrogen sources. These two facts suggest that farmers could find Arthrobotrys an important tool in combating nematode infestations. Which of the following research questions would make a good starting point for developing such a defense against plant-sucking nematodes?

Does nitrogen fertilization of crops affect the likelihood that Arthrobotrys will trap and kill nematodes?

Referring to Simard et al. (1997), what is the result that would most strongly refute their hypothesis? [Hypothesis: Sugars made by one plant during photosynthesis can travel through a mycorrhizal fungus and be incorporated into the tissues of another plant.(Plant Figure A)

Either carbon-13 or carbon-14 is found in the cedar seedling's tissues.

Data were collected from the heterocysts of a nitrogen-fixing cyanobacterium inhabiting equatorial ponds. Study the graph and choose the most likely explanation for the shape of the curve.

Enough oxygen (O2) enters heterocysts during hours of peak photosynthesis to have a somewhat inhibitory effect on nitrogen fixation.

100,000 human deaths every year.

Entamoeba histolytica

Examine the effect of AMF species on Sanguisorba officinalis. Which of the following conclusions can be correctly drawn from the data?

Growth is best with AMF species A.

Degradation rates of cell walls extracted from Orchard grass by the monoculture system to assess the relative contributions of digestion by bacterial (square), protozoan (triangle), and fungal (diamond) systems, and all components (closed circle) as a control. The lowercase letters above the spots indicate statistical significance; mean values with different letters are significantly different (P < 0.05). Which of the following conclusions can be drawn correctly from the data?

Fungi contribute as much to cell wall degradation as all the potential mutualists together.

Deutromycetes

Fungi in this phylum do not appear to have a sexual phase in their life cycle

Why are mycorrhizal fungi superior to plants at acquiring mineral nutrition from the soil?

Fungi secrete extracellular enzymes that can break down large molecules.

Prokaryotic and Eukaryote cells_________________.

Have different structures.

Mitochondria are thought to be the descendants of certain alpha proteobacteria. They are, however, no longer able to lead independent lives because most genes originally present on their chromosomes have moved to the nuclear genome. Which phenomenon accounts for the movement of these genes?

Horizontal Gene Transfer

The Gd mat on the fur of the bats should be expected to consist of ________.

Hyphae

Based on the idea that fungi have pores between their cell walls that allow cytoplasm to move from one end of the mycelium to the other, which of the following hypotheses is the most plausible?

If a single mycorrhizal fungus formed symbiotic associations with more than one tree, carbon could travel from one plant to another.

Refer to the study by Poulsen et al. and the figure above. Latrunculin A is a reversible toxin that disrupts the formation of actin fibers. A culture of a particular species of diatom was treated with this toxin diluted in a buffer, while another culture was treated only with the buffer (no toxin; control). The motility of cells in each culture was assessed by counting the number of cells that were moving during a defined period of time. Which of the following conclusions is reasonable based on the above figure?

In this species of diatom, fully formed actin fibers are necessary for movement.

An individual mixotroph loses its plastids, yet continues to survive. Which of the following most likely accounts for its continued survival?

It engulfs organic material by phagocytosis or absorption.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. Which of the following statements about the cell wall is most probable?

It has an outer membrane of lipopolysaccharide.

The figure below depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). How is the recipient cell different at Time D than it was at Time A?

It has different sequence of base pairs

You have found a new prokaryote. What line of evidence would support your hypothesis that the organism is a cyanobacterium?

It is able to form colonies and produce oxygen.

The Mitosome of Giardia has no DNA within it. If it did contain DNA, then what predictions should we be able to make about its DNA?

It is circular, has few introns and is not associated with histone proteins.

Asexual reproduction in yeasts occurs by budding. Due to unequal cytokinesis, the "bud" cell receives less cytoplasm than the parent cell. Which of the following statements should be an accurate characterization of the smaller cell until it reaches the size of the larger cell?

It should produce fewer fermentation products per unit time.

_______________is an important group of protists that produce________, a substance useful to humans.

Kelp, Algin

In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. Which term best describes what has occurred among the experimental populations of cells over this eight-year period?

Microevolution.

Simard et al. (1997) further hypothesized that if reciprocal transfer did occur, it would be a source-sink relationship driven by photosynthetic rates. That is, if one seedling is in full sun and the other in deep shade, there will be a net movement of carbon from the seedling in full sun to the one in deep shade. If a shade were placed over the birch seedlings and the cedar, and the Douglas fir was left in full sun, what result could Simard and colleagues expect?

More 13C would be found in the birch than 14C in the Douglas fir.

A P. bursaria cell that has lost its zoochlorellae is aposymbiotic. If aposymbiotic cells have population growth rates the same as those of healthy, zoochlorella-containing P. bursaria in well-lit environments with plenty of prey items, then such an observation would be consistent with which type of relationship?

Mutualistic

Some fungal species live in plants and can kill herbivores that feed on the plant. What type of relationship does this fungus have with its host?

Mutualistic

Based on the van der Heijden et al. (1998) graphs in the figure, which of the following is the best description of the data supporting the idea that a plant species did not form mycorrhizae with a fungus? Its biomass is greatest when ________.

No AMF are present.

Based on graphs e and f, which is the most well-supported prediction for the effect on total plant biomass if AMF diversity were increased to eight species?

No effect is predicted, because the dominant species is unaffected by AMF diversity.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. In which feature should one be able to locate a complete chromosome of this bacterium?

Nucleoid

Nitrogenase, the enzyme that catalyzes nitrogen fixation, is inhibited whenever free oxygen (O2) reaches a critical concentration. Consequently, nitrogen fixation cannot occur in cells wherein photosynthesis produces free O2. Consider the colonial aquatic cyanobacterium, Anabaena, whose heterocysts are described as having "...a thickened cell wall that restricts entry of O2 produced by neighboring cells. Intercellular connections allow heterocysts to transport fixed nitrogen to neighboring cells in exchange for carbohydrates." Given that the enzymes that catalyze nitrogen fixation are inhibited by oxygen, what mechanism might nitrogen-fixing prokaryotes use to protect these enzymes from oxygen?

Package the nitrogen fixation enzymes in membranes that are impermeable to nitrogen gas (N2)

At which stage of a basidiomycete's life cycle would reproduction be halted if an enzyme that prevented the fusion of hyphae was introduced?

Plasmogamy

Which of the following traits do archaeans and eukaryotes share?

Presence of Introns

It has been hypothesized that fungi and plants have a mutualistic relationship because plants make sugars available for the fungi's use. What is the best evidence in support of this hypothesis?

Radioactively labeled sugars produced by plants eventually show up in the fungi with which they are associated.

A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. This alga is most likely a type of _____.

Red Algae

Suppose that S. schenkii had initially been classified as a deuteromycete. Asci were later discovered in the pus that oozed from an ulcerated lymph node, and the spores therein germinated, giving rise to S. schenkii yeasts. Which of these statements make sense on the basis of this information?

S. schenkii should be reclassified; S. schenkii yeasts belonging to two different mating strains were introduced by the same thorn prick.

Given its mode of reproduction and internal structures, which of the following should be expected to occur in Giardia at some stage of its life cycle?

Segregation (separation) of Daughter Chromosomes.

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the question(s) below Which species might include cells that are Hfr cells?

Species D

When adult amphibian skin harbors populations of the bacterium Janthinobacterium lividum (Jl), chytrid infection seems to be inhibited. Which of the following represents the best experimental design to test whether this inhibition is real?

Take infected amphibians and assign them to two populations. Leave one population alone; inoculate the other with Jl. Measure the rate at which infection proceeds in both populations.

The ascomycete Brachiola gambiae parasitizes the mosquito Anopheles gambiae. Adult female mosquitoes must take blood meals for their eggs to develop, and it is while they take blood that they transmit malarial parasites to humans. Male mosquitoes drink flower nectar. If humans are to safely and effectively use Brachiola gambiae as a biological control to reduce human deaths from malaria, then which of the following statements should be correct?

The ascomycete should kill the mosquitoes before the malarial parasite they carry reaches maturity and should not be harmful to other insects.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. The cell also lacks F factors and F plasmids. Which of the following statements about the bacteria is most probably accurate?

The bacterium cannot donate DNA through conjugation with another cell.

Living diatoms contain brownish plastids. If global warming causes blooms of diatoms in the surface waters of Earth's oceans, how might this be harmful to the animals that build coral reefs?

The coral animals' endosymbiotic dinoflagellates may get "shaded out" by the diatoms.

Humans have immune systems in which lymph nodes are important, because many white blood cells (phagocytes and lymphocytes) reside there. Given that a successful infection by S. schenkii damages lymph nodes themselves, which of the following is most probable?

The fungal conversion from yeast to hyphal morphology allows such fast growth that the body's defenses are at least temporarily overwhelmed.

Fungi have an extremely high surface-to-volume ratio. What is the advantage of this characteristic to an organism that gets most of its nutrition through absorption?

The high ratio allows for more material to be acquired from the surroundings and transported through the cell membrane.

Predict the results if the researchers had used a control that contained no potential mutualists (negative control).

The negative control would have very little cell wall degradation.

The Neurospora genome is quite compact, lacking many of the noncoding DNA sequences that occur in humans and many other eukaryotes. Which of the following are probable benefits of the compactness of the genome?

The organism saves energy during cell division because fewer DNA bases must be duplicated.

Which of the following observations about flagella is accurate and is consistent with the scientific conclusion that the flagella from eukaryotes and bacteria evolved independently?

The protein structure and the mechanism of movement in eukaryotes flagella are different from those of bacteria flagella.

If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result?

The recycling of nutrients would be greatly reduced, at least initially.

Many parasitic members of the excavates lack plastids and have highly reduced mitochondria. Which of the following statements explains these observations?

These parasites live in dark, low-oxygen conditions and therefore loss of genes for plastids and mitochondria did not result in lower fitness.

In graph b in the figure, which of the following best explains the data given about Lotus corniculatus?

This plant forms multiple AMF associations, growing best with increased fungal diversity.

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following question. How many of these species probably have a cell wall that consists partly of an outer membrane of lipopolysaccharide?

Three species

In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. If the experimental population of E. coli lacks an F factor or F plasmid, and if bacteriophages are excluded from the bacterial cultures, then beneficial mutations might be transmitted horizontally to other E. coli cells via ________.

Transformation.

Truffles are the fruiting bodies of certain fungi whose mycelium grows below ground. The truffle is also underground and can be detected by many mammals, which eat the truffle and expel the spores with their feces. Which of the following statements is likely accurate with respect to this interaction?

Truffles produce an odor that mammals can detect and find attractive.

Jams, jellies, preserves, honey, and other foods with high sugar content hardly ever become contaminated by bacteria, even when the food containers are left open at room temperature. This is because bacteria that encounter such an environment ____.

Undergo death as result of water loss from cell.

Refer to the study by Poulsen et al. and the figure above. The data graphed in the figure could be an artifact if latrunculin A kills this species of diatoms (that is, that may be why the cells are not moving). Which of the following would be the best evidence that latrunculin A is not killing the cells?

When the toxin was washed off the culture, the cells began to move again.

For several decades now, amphibian species worldwide have been in decline. A significant proportion of the decline seems to be due to the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Chytrid sporangia reside within the epidermal cells of infected animals, animals that consequently show areas of sloughed skin. They can also be lethargic, which is expressed through failure to hide and failure to flee. The infection cycle typically takes four to five days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100%; other species seem able to survive the infection. If infection primarily involves the outermost layers of adult amphibian skin, and if the chytrids use the skin as their sole source of nutrition, then which term best applies to the chytrids?

aerobic chemoheterotroph

The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to _____.

an extensive surface area well suited for invasive growth and absorptive nutrition

The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to _________________.

an extensive surface area well suited for invasive growth and absorptive nutrition

Predict the most likely outcome of fertilizing areas of ocean with iron.

an increase in diatom populations that will contribute to reducing atmospheric CO2

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. This bacterium derives nutrition by digesting human intestinal contents. Thus, this bacterium is an ________.

anaerobic chemoheterotroph

Consider the following data: (a) Most ancient eukaryotes are unicellular. (b) All eukaryotes alive today have a nucleus and cytoskeleton. (c) Most ancient eukaryotes lack a cell wall. Which of the following conclusions could reasonably follow the data presented? The first eukaryote may have been _____________.

capable of phagocytosis

The predatory bacterium Bdellovibrio bacteriophorus drills into a prey bacterium and, once inside, digests it. In an attack upon a gram-negative bacterium that has a slimy cell covering, what is the correct sequence of structures penetrated by B. bacteriophorus on its way to the prey's cytoplasm?

capsule, lipopolysaccharide membrane, peptidoglycan, phospholipid membrane.

A fish that has been salt-cured subsequently develops a reddish color. You suspect that the fish has been contaminated by the extreme halophile Halobacterium. Which of these features of cells removed from the surface of the fish, if confirmed, would support your suspicion?

cell walls that lack peptidoglycan and are isotonic to conditions on the surface of the fish

You observe the gametes of a fungal species under the microscope and realize that they resemble animal sperm. To which of the following groups does the fungus belong?

chytrids

Water's density and, consequently, its buoyancy decrease at warmer temperatures. Considering the impact of temperature, and the table above, in which environment should diatoms sinking be slowest?

cold seawater

Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gather at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae. A P. bursaria cell that has lost its zoochlorellae is aposymbiotic. If aposymbiotic cells have population growth rates the same as those of healthy, zoochlorella-containing P. bursaria in well-lit environments with plenty of prey items, then such an observation would be consistent with which type of relationship?

commensalistic

The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?

cyanobacteria - green algae - land plants

Super cells characteristic of plasmodial slime molds result when which one of the following common cellular processes does not occur?

cytokinesis

Broad-spectrum antibiotics inhibit the growth of most intestinal bacteria. Consequently, assuming that nothing is done to counter the reduction of intestinal bacteria, a hospital patient who is receiving broad-spectrum antibiotics is most likely to become _____.

deficient in certain vitamins and nutrients

The figure below depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). What process is occurring at Time C that is decreasing the DNA content?

degradation of DNA that was not retained in the recipient's chromosome.

Which of the following reasons provides the best explanation for the use of a control that contained all potential mutualists? Comparison to a fraction that contained all potential mutualists allowed the researchers to ________.

determine how much each potential mutualist contributed to cell wall degradation.

Sexual reproduction has not been observed in Bd. If its morphology and genetics did not identify it as a chytridiomycete, then to which fungal group would Bd be assigned?

deutromycetes

You are given the task of designing an aquatic protist that is a primary producer. It cannot swim on its own, yet must stay in well-lit surface waters. It must be resistant to physical damage from wave action. It should be most similar to a(n) _____.

diatom

which organism is a producer?

diatoms

Previously recognized similarities that seemed to connect slime molds and fungi are now considered to be ________.

examples of convergent evolution

When a mycelium infiltrates an unexploited source of dead organic matter, what are most likely to appear within the food source soon thereafter?

fungal enzymes

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. This bacterium's ability to survive in a human who is taking penicillin pills may be due to the presence of ________.

gram-negative cell wall.

A particular species of protist has obtained a chloroplast via secondary endosymbiosis. You know this because the chloroplasts ___________________.

have three or four membranes.

Plasmogamy can directly result in which of the following?

heterokaryotic cells and dikaryotic cells

The thermoacidophile Sulfolobus acidocaldarius lacks peptidoglycan, but still possesses a cell wall. Which of the following statements is likely to be an accurate description of this species?

it could inhabit hydrothermal springs.

Which of the following traits do archaeans and bacteria share?

lack of a nuclear envelope and presence of plasma membrane.

Water's density and, consequently, its buoyancy decrease at warmer temperatures. Based on this consideration and using data from the table above, at which time of year should one expect diatoms to be storing excess calories mostly as oil?

late summer

Mycorrhizae are to the roots of vascular plants as endophytes are to the ________ of vascular plants.

leaf mesophyll

If haustoria from the fungal partner were to appear within the photosynthetic partner of a lichen, and if the growth rate of the photosynthetic partner consequently slowed substantially, then this would support the claim that _____.

lichens are not purely mutualistic relationships

The motility that permits P. bursaria to move toward a light source is provided by _____.

many cilia

If plaque on teeth is actually a biofilm, which of the following characteristics would you expect to find in plaque?

multiple species of bacteria, production of chemicals that attract other bacteria, and production of chemicals that allow the bacteria to adhere to enamel

In a hypothetical situation, a bacterium lives on the surface of a leaf, where it obtains nutrition from the leaf's nonliving, waxy covering while inhibiting the growth of other microbes that are plant pathogens. If this bacterium gains access to the inside of a leaf, however, it causes a fatal disease in the plant. Once the plant dies, the bacterium and its offspring decompose the plant. What is the correct sequence of ecological roles played by the bacterium in the situation described here?

mutualist, pathogen, nutrient recycler

Which term best describes the symbiotic relationship of well-fed P. bursaria to their zoochlorellae?

mutualistic

Arrange the following in order from largest to smallest, assuming that they all come from the same fungus.

mycelium, basidiocarp, gill, basidium, basidiospore

If the mitosomes of Giardia contain no DNA, yet are descendants of what were once free-living organisms, then where are we likely to find the genes that encode their structures, and what accounts for their current location there?

nucleus, horizontal gene transfer.

In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structures?

plasmids, nucleoid, and endospore.

Trypanosome infections evade attacks by host immune systems through which of the following mechanisms?

production of new cell-surface proteins with a different molecular structure by each new generation.

If all fungi in an environment that perform decomposition were to suddenly die, then which group of organisms should benefit most, due to the fact that their fungal competitors have been removed?

prokaryotes

you are given the task of designing an aerobic, mixotrophic protist that can perform photosynthesis in fairly deep water (for example, 250 meters deep) and can also crawl about and engulf small particles. With which two of the following structures would you provide your protist?

pseudopods and chloroplasts from red algae

In a hypothetical situation, the genes for sex pilus construction and for tetracycline resistance are located on the same plasmid within a particular bacterium. If this bacterium readily performs conjugation involving a copy of this plasmid, then the result should be the ______________.

rapid spread of tetracycline resistance to other bacteria in that habitat.

In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. Compare the bacteria in the figure above in generation 1 and generation 20,000. The bacteria in generation 1 have a greater ________.

reliance on glycolytic enzymes.

In most fungi, karyogamy does not immediately follow plasmogamy, which consequently ____________.

results in heterokaryotic or dikaryotic cells.

After cytokinesis occurs in budding yeasts, the daughter cell has a ____________.

similar nucleus and less cytoplasm than the mother cell.

Compared to eukaryotes, prokaryotes are ________.

simpler morphologically, but not more evolutionarily primitive

In which of the following human mycoses should one expect to find a growth pattern most similar to that of the mycelium that produced the fairy ring?

skin mycoses

Which of the following observations about flagella is accurate and is consistent with the scientific conclusion that the flagella from archaea and bacteria evolved independently?

the protein structure in the flagella are different.

Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. These two groups differ in ________.

their sources of carbon.

Which of the following is characteristic of ciliates?

they are often multinucleate

Which of the following describe all existing bacteria?

tiny, ubiquitous, metabolically diverse

What is the goal of bioremediation?

to clean up areas polluted with toxic compounds by using bacteria